Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in PYTHON):

Solution:
import sys
def transpose(a):
    art=[]
    aux=[]
    for i in xrange(len(a[0])):
        for j in xrange(len(a)):
            aux.append(arr[j][i])
        art.append(list(aux))
        aux=[]
    return art
n,m=map(int,raw_input().split())
arr=[map(int,raw_input().split()) for _ in xrange(n)]
if n<=m:
    total=0
    ans=[]
    for i,row in enumerate(arr):
        x=min(row)
        ans.append(x)
        if x>0:
            for j in xrange(m):
                arr[i][j]-=x
    ansc=[]
    j=0    
    while j<m:
        x=999
        i=0
        for i in xrange(n):
            x=min(x,arr[i][j])
        ansc.append(x)    
        if x>0:
            for i in xrange(n):
                arr[i][j]-=x

        j+=1


    for i in xrange(n):
        for j in xrange(m):
            if arr[i][j]!=0:
                print -1
                sys.exit()

    print sum(ans)+ sum(ansc)
    for i,item in enumerate(ans,start=1):
        if item>0:
            z=item
            while z>0:
                print "row",i
                z-=1

    for i,item in enumerate(ansc,start=1):
        if item>0:
            z=item
            while z>0:
                print "col",i
                z-=1

else:
    #print 'More rows'
    arr=transpose(arr)
    n,m=m,n
    #for r in arr:print r
    total=0
    ans=[]
    for i,row in enumerate(arr):
        x=min(row)
        ans.append(x)
        if x>0:
            for j in xrange(m):
                arr[i][j]-=x
    ansc=[]
    j=0    
    while j<m:
        x=999
        i=0
        for i in xrange(n):
            x=min(x,arr[i][j])
        ansc.append(x)    
        if x>0:
            for i in xrange(n):
                arr[i][j]-=x

        j+=1


    for i in xrange(n):
        for j in xrange(m):
            if arr[i][j]!=0:
                print -1
                sys.exit()

    print sum(ans)+ sum(ansc)
    for i,item in enumerate(ans,start=1):
        if item>0:
            z=item
            while z>0:
                print "col",i
                z-=1

    for i,item in enumerate(ansc,start=1):
        if item>0:
            z=item
            while z>0:
                print "row",i
                z-=1